Every evening when I go out to shut my chickens in, there are always only one or two on the roosts! I have fashioned both the roosts and the top of the nest boxes for them to sleep on, but recently more and more chickens want to sleep on top of the nest box. The roosts are several inches higher than the nest boxes. Their roosts are at least four inches wide, so I wouldn't think it would be foot-warming problem? It has been getting a bit colder. Could I have mites that hide in my wooden roosts, and that's why they don't like to sleep there? I've looked, but all I've ever found on my chickens are lice. I don't mind them sleeping on the nest boxes since I made the top of them easy to clean, but it puzzles me why they don't want to use the perfectly good roosts. Age: They are all full grown, varying in ages between 8 months and 4 years.